Piston



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u :n what@ ATEN'E Ft Y IN GURPUTIUN, Uh' METMML, ltCHIG-Mll tllttllmlllltonttuuation :tn part at application tlcrtall rta. tithttt, ated uthirtyat, that. 'this application ed arch ia, raar.

YlFhis invention relates to pistons, particularly to pistons tor use ininternal coinhus tion engines, and airns to improve the construction andoperative results ot such pistons Nll have previously disclosed in myPatent lilo. l,4l38,l82 granted Decernher 5, i922, the use ot relativeyinenpansihle struts to over come the ditdculties due to the high rateoit thermal expansion ot certain light-Weight piston materials, such asaluminum alloys. l he Apresent invention aims to utilise the principlesheretofore disclosed and to produce an improved piston hy thecooperation ot certain novel tentures oit construction hereinafter morehilly set 'torth |llhe presentl application is in part a continuationot' my application @erial lilo.. l25.,- 339 tiled duly 2h, i926..

ln the drawings, liig. l is an elevation partly in section oit a pistonemhodying the invention;

lllig. 2 is a section on line hun ot llig. l;

llig. d is a section on line h--d ot llig. l;

Fig. t is a section on line tl-ll ot lli t;

lilig., 5 is an enlarged sectional detai shovving a modihed torin otjoint, hetueen the end oit the strut and the hearing portions; lllig. tis a vievv 'siar to liig.. 5 shovving `a turther modihcation.. y

Reiterring to the drawings more specifically, the piston, which ispreterahly termed ot light-Weight material, such as an alloy oitaluminum, comprises a head portionand a slrirt` portion, the latter termapplying to the rione lying helovv the head.

The piers l0, vvhich depend Itrom the head, are reintorced internally hyrihs ll and ea:- ternally hy a rih l2, and have the piston pin hosses i3lormed therein. Below the pin hosses the piers connect vvith thehorizontal arcuate vvehs 1d, which are joined to the lower circular partl5 ot the shirt. @n op osite sides ot the slrirt and located 90 from t epin hosses, the semi-cylindrical hearing portions it and l?ertendupwardly from the circular part, l5 ot the shirt. These hearingportions are discontinuous from the` head and from the upper part of thepiersand have hom0. gaseous connections with the piers through tterlaltta.. ltt'nlittt.

the ring l5 and vvehs lll. The circular portion l5 is reinforced at'points directly helovv the opening 2U vvhich lie hetueen the piers andthe hearin portions. This reinltorcing may he accornp ished in anyconvenient inanner as -hy thickening the slnrt at these points to tor-mthe pads 2l.

lFtiston ring grooves l@ are cnt into the side ot the piston head, thelovvest groove heing positioned so that the slots 19, hetvveen thehearing portions l5 and li' and the head, are located at the hottona otthis groove.

The shirt is provided vvith a slotor slots eatending upvvardly trom thelovver end thereozt as at 22.

.di pair ot dat, plate-lilac struts 2d entend hetvveen the hearingportions, the struts heing located above the anis oit the piston pinhosses and having their intermediate portons embedded in the materialAoit the piers. Positioning holes 25, formed in the strut., tornaineanshy vvhich the strut is accurately positioned and positivelyheldagainst all movement during the operation ot casting. Additionalapertures 2li are formed in the strut and the material oit the pier ispermitted to idovv through these apertures to strengthen and soliditythe pier and assist in holding 4 f y this construction the is positivelyi held hyi the material ont the pier, the ends ot lill Stili the strutlosing merely propped against the hearing portions. This tree jointloetween the struts and hearing portions reduces the.

amount of heat transmitted through the piers andstruts to the hearingportions. As the piston cools after casting the hearing portions tend tocontract toward each other, ut the struts hold them out in positlons dosigned to give @min clearance that will prevent piston slap'when themotor is cold,

thereby setting up certain stresses in the bearing portions. As thepiston warms up during operation the increase in temperature tends torelieve the stresses, but does not cause the bearing portions to expandaway from the struts, as the operating temperatures are never as high asthe casting temperature.

y Obviously any suitable joint may be used between l the strut end 'andthe bearing por.

tions, the desired result being ajoint in which the bearing portion ismerely propped agamst the end of the strut. In the )omt of Fig. 6

the end of the strut is left straight and merely buts againts the end ofthe bearing portlons, while in Fig. 5 the end ofthe strut is bent toform an L-shaped foot 28.

It will be clear from Fig. 3 that the center of thejoint between the endof the strut and the bearing portion is on the line w-b, and that thelines a-'-b are closer together than the lines o-Z,'thecenter lines ofthe struts.

This construction permits keeping the main parts of the struts spreadfar enough to suit certain piston designs, and at the same time reducesthe effective length of aluminum be'- tween the'ends of the struts,thereby reducing the amount of aluminum expansion that has a bearingonthe resultant skirt expansion.

1. A piston comprising a head, sections depending from the head andhaving piston pin bosses secured thereto, bearing portions formed oflight-weight material, and a` pair,

of struts of material lessexpansible than the material of the bearingportions, the intermediate portion of each strut being embedded in aboss-carrying section, the ends of the strut having free surface contactwith the bearing portions.

2. Apiston'comprising a head, sections de- `pending vfrom the head andhaving piston-pin bossessecuredthereto,bearingportionsformed oflight-'weight material, a pair of struts of material less expansiblethan the material of the bearing portions, the intermediate portion ofeach strut being embeddedin a bosscarrying section,the ends of the struthaving free surface contact with the `bearing portions, there being aconneetion'between the bearing portions andthe depending sections inaddition to the struts, said connection bepending from the head andhaving piston pin osses secured thereto, bearing portions formed oflight-weight material, a pair of struts ofsmaterial less expansible thanthe material of the bearing portions, the intermediate portion of eachstrut being embedded in a boss-carrying section, the ends of the struthaving free surface contact with tlie bearing portions, the struts beinglocated inithe vertical zones ofthe piston pin bosses and there being aconnection between the bearing vportions and the depending sections inaddition to the struts, said connection being designed to carry thebearing portions.

5. A piston comprising a head, sections depending from the head andhaving piston pin bosses f secured thereto, bearing portions formed oflight-weight material, and a pair of iat, plate-like struts 'of materialless eXpansible than the material of the bearing portions, theintermediate portion of each strut being embedded in a boss-carryingsection, the ends ofthe strut having free surface contact with thebearing portions.

6. A piston comprising a head, sections depending from the head andhaving piston pin bosses secured thereto, bearing portions formed oflight-weight material, a pair of flat, plate-like struts of materialless expansible than the material of the bearing portions, theintermediate portion of each strut being embedded in a boss-carryingsection, the ends of the strut having free surface contact with thebearing portion, therebeing a connection between the bearing portionsand the depending sections in addition to the struts, said connectionbeing designed to carry the bearing portions.

7. A piston comprising a head, sections depending from the head andhaving piston pin bosses secured thereto, bearing portions formed oflight-weight material, a pair of flat, plate-like struts of materialless expansible than the material of the bearing portions,` theintermediate portion of each strut being embedded in a boss-carryingsection, the ends of the strut having free surface contact with thebearing portions, the struts being located in the vertical zones of thepiston pin bosses.

' 8. A piston comprising a head, sections depending from the head andhaving piston pin bosses secured thereto, bearing portions formed oflight-weight material, a pair of Hat, late-like struts of material lessexpansilble than the material of the bearing portions, the -intermediateportion of each strut being embedded in a boss-carrying section, theends of the strut having free surface contactwith the bearing portions,the struts being located in the vertical zones of the iston pin bossesand there being aconnection Between the bearing portions and thedepending sections in addition to the struts, said connection beingdesigned to carry the bearing portions.

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49. A piston comprising a head, piers def pending trom the head, pistonpm bosses formed in the'piers, bearing portions formed et light-weightmaterial, a pair .of fla-t, platelike struts of material less expansiblethan the material et the bearing portions, the intermediat-e portion ofeach strut being embedded in a pier, the ends of the struts having freecontact with the bearing portions, and there being a connection betweeneach bearing portion and each pierl in addition to the struts, saidconnection being designed to carry the bearing portions.

l0. A pistonromprising' a head, piers-depending trom the head, pistonpin bosses termed in the piers, bearmg portions formed ot light-weightmaterial, a pair et dat, platelike struts Vot mateljial -less expansiblethan the material et the bearin portions, the intermediate portion eteac 'strut being embedded in a pier, the ends et the struts haying treecontact .with the bearing portions, the struts being located in theVertical planes ot the piston pin bosses, and there be` ing a connectionbetween each bearing portion and each pier in addition te the struts,said connection being designed to carry Ithe bearing portions.

il. .ti piston comprising a head, piers de pending trom the head, pistonpin bosses termed in the piers, bearing portions termed ot light-weightmaterial, and a pair et dat, plate-lilxestruts ot material lessexpansible than the material ot the bearing portions, each strutextending between the bearing pertions and having. its intermediateportion embedded in the material et a pier, the intermediate portion otthe strut being termed with an aperture, the material et extendingthrough the aperture.

12. A piston comprising a head, sections depending trom the head andharing piston pin bosses secured thereto, bearing portions the pier.termed ot light-weight material, and a pair ot struts et material lessexpansible than the material ot the bearing portions extending betweenthe `bearing portions, the centers ot contact ot thestruts with abearing portion being closer together than the longitudinal centers etthe struts.

t3. l piston comprising a head, a pair ot struts ot relativelyineansible material, a

cylinder bearing portion haring a cast-in titi t I pending trom the titljoint with an end et each strut, the centersl otthe cast-in joints beingIcloser together than the longitudinal centers ot the intermediateportion et the struts.f\

il. it piston cemplrising a head, piers deead, piston pin bosses termedin the piers, bearing portions termed ot'light-weight material, and apair ot dat,

plate-lilre struts" et material less expansible than the material et thebearing portions,

each strut extending between the bearing a portions .and having itsintermediate portion embedded in the material of a pier, the strut beingformed with a plurality of apertures pin bosses, the skirt being formedwith a cir- I cular portion lying below the bosses and withcylinder-bearing.portions extending upwardly from the circular portion,the outer wall of the skirt having openings therethrough between thepiers and the cylinder-bearing porv tions, and a horizontal arcuate webextending across the lower end et each pier and crossing the zones ofthe openings, the circular portioni being connected'to the arcuate webs.

.16. A.' piston comprising a headand a skirt, piers depending from thehead' and carrying pin bosses, the skirt being termed with a circularportion lying below the bosses and with cylinder-bearing ortionsextending up-` wardly trom the circu ar portion, one et thecylinder-bearing portions being termed with a slot extending upwardlytrom the bottom et the piston, the outer wall et the skirt having oenings therethrough between the piers and t e cylinder-bearing portions,and a boriaontal arcuate web extending across the lower end ot each pieranderossing the zones et the openings, the circular portion beingconnected te the arcuate webs.V i i lt.. .il piston comprising a headand a slrirt, piers depending trom the head and carrying pin bosses, theskirt being termed with a cirv cular ortion lying below the bosses andwith Mld portion to the

